Such crane controller is known for example from DE 10 2008 024513 A1. There is provided a prediction device which predicts a future movement of the cable suspension point with reference to the determined current heave movement and a model of the heave movement, wherein the path controller takes account of the predicted movement when actuating the hoisting gear.
The known crane controller however is not sufficiently flexible for some requirements. In addition, problems may arise in the case of a failure of the heave compensation.
Therefore, it is the object of the present disclosure to provide an improved crane controller with an active heave compensation and an operator control.
According to the present disclosure, this object is solved in a first aspect according to claim 1 and in a second aspect according to claim 4.
In a first aspect, the present disclosure shows a crane controller for a crane which includes a hoisting gear for lifting a load hanging on a cable. There is provided an active heave compensation which by actuating the hoisting gear at least partly compensates a movement of the cable suspension point and/or a load deposition point due to the heave. Furthermore an operator control is provided, which actuates the hoisting gear with reference to specifications of the operator. According to the present disclosure, a division of at least one kinematically constrained quantity of the hoisting gear is adjustable between heave compensation and operator control. In this way, the crane operator himself can split up the at least one kinematically constrained quantity of the hoisting gear and thereby determine which part of it is available for the compensation of the heave and which part of it is available for the operator control.
The at least one kinematically constrained quantity of the hoisting gear for example can be the maximum available power and/or maximum available velocity and/or maximum available acceleration of the hoisting gear.
The division of the at least one kinematically constrained quantity of the hoisting gear therefore can comprise a division of the maximum available power and/or maximum available velocity and/or maximum available acceleration of the hoisting gear.
Advantageously, the division of the at least one kinematically constrained quantity is effected by at least one weighting factor, by which the maximum available power and/or velocity and/or acceleration of the hoisting gear is split up between the heave compensation and the operator control. In particular, the maximum available velocity and/or the maximum available acceleration of the hoisting gear can be split up by the crane operator between heave compensation and operator control.
Advantageously, the division is steplessly adjustable at least in a partial region. It thus becomes possible for the crane operator to sensitively split up the at least one kinematically constrained quantity of the hoisting gear.
According to the present disclosure, it can furthermore be possible to switch off the heave compensation by assigning the entire at least one kinematically constrained quantity of the hoisting gear to the operator control. It thus becomes possible to at the same time completely switch off the active heave compensation via the adjustment of the division.
Advantageously, a stepless adjustment of the division of the at least one kinematically constrained quantity of the hoisting gear is possible proceeding from and/or towards an operator control completely switched off. This enables a steady transition between a pure operator control and an active heave compensation.
In a second aspect, the present disclosure comprises a crane controller for a crane which includes a hoisting gear for lifting a load hanging on a cable. The crane controller comprises an active heave compensation which by actuating the hoisting gear at least partly compensates the movement of the cable suspension point and/or a load deposition point due to the heave. Furthermore an operator control is provided, which actuates the hoisting gear with reference to specifications of the operator. According to the present disclosure, the controller includes two separate path planning modules via which trajectories for the heave compensation and for the operator control are calculated separate from each other. In the case of a failure of the heave compensation, the crane thereby can still be actuated via the operator control, without a separate control unit having to be used for this purpose and without this resulting in a different operating behavior. Advantageously, in the two separate path planning modules desired trajectories of the position and/or velocity and/or acceleration of the hoisting gear each are calculated.
Furthermore advantageously, the trajectories specified by the two separate path planning modules are added up and used as setpoint values for the control and/or regulation of the hoisting gear.
Furthermore, it can be provided that the control of the hoisting gear feeds back measured values to the position and/or velocity of the hoisting winch and thus compares the setpoint values with actual values. Furthermore, the actuation of the hoisting gear can take account of the dynamics of the drive of the hoisting winch. In particular, a corresponding pilot control can be provided for this purpose. Advantageously, the same is based on the inversion of a physical model of the dynamics of the drive of the hoisting winch.
Advantageously, the two separate path planning modules each separately take account of at least one constraint of the drive and thereby generate target trajectories which can actually be approached by the hoisting gear.
Advantageously, the crane controller splits up at least one kinematically constrained quantity between heave compensation and operator control. In particular, the maximum available power and/or the maximum available velocity and/or the maximum available acceleration of the hoisting gear is split up between the heave compensation and the operator control.
Advantageously, the trajectories in the two separate path planning modules then are calculated taking into account the respectively assigned at least one kinematically constrained quantity, in particular the maximum available power and/or velocity and/or the maximum available acceleration which is accounted for the heave compensation and the operator control, respectively.
By this division of the at least one kinematically constrained quantity, the control variable constraint possibly is not utilized completely. The division of the at least one kinematically constrained quantity however provides for using two completely separate path planning modules, which each independently take account of the drive constraint.
The first and the second aspect according to the present disclosure each are claimed separately and can be implemented independently. Particularly advantageously, however, the two aspects according to the present disclosure are combined with each other.
In particular, the use of two separate path planning modules according to the second aspect of the present disclosure provides for a particularly easy adjustability of the division of the at least one kinematically constrained quantity. In particular, it can be specified by the crane operator how much of the at least one kinematically constrained quantity is available for the operator control and the heave compensation, with this division then being taken into account as constraint by the two path planning modules when calculating the target trajectories for actuating the hoisting gear.
In a crane controller according to one of the above-described aspects, the heave compensation according to the present disclosure can include an optimization function which calculates a trajectory with reference to a predicted movement of the cable suspension point and/or a load deposition point and taking into account the power available for the heave compensation. In particular, there is calculated a trajectory for actuating the hoisting gear, which taking into account the power available for the heave compensation compensates the predicted movement of the cable suspension point and/or a load deposition point as well as possible. In particular, the trajectory can minimize the residual movement of the load due to the movement of the cable suspension point and/or a differential movement between load and load deposition point, which occurs due to the heave.
The crane controller according to the present disclosure advantageously comprises a prediction device which predicts a future movement of the cable suspension point and/or a load deposition point with reference to the determined current heave movement and a model of the heave movement, wherein a measuring device is provided, which determines the current heave movement with reference to sensor data. In particular, the prediction device predicts the future movement of the cable suspension point and/or a load deposition point in vertical direction. The movement in vertical direction on the other hand can be neglected.
The prediction device and/or the measuring device can be configured such as is described in DE 10 2008 024513 A1.
The operator control furthermore can calculate a trajectory with reference to specifications of the operator and taking into account the at least one kinematically constrained quantity available for the operator control. Advantageously, the operator control thus also takes account of the at least one kinematically constrained quantity maximally available for the operator control and thus calculates a trajectory for actuating the hoisting gear from specifications of the operator.
By taking into account the respectively available at least one kinematically constrained quantity, it is ensured that the hoisting gear actually can follow the specified trajectories. Advantageously, the determination of the trajectories each is effected in the above-described path planning modules.
Advantageously, the crane controller includes at least one control element via which the crane operator can adjust the division of the available at least one kinematically constrained quantity and in particular can specify the weighting factor.
In the crane controller according to the present disclosure, the division of the available at least one kinematically constrained quantity advantageously can be varied during the lift. The crane operator thereby is able for example to provide more power for the operator control, when faster lifting is desired. On the other hand, more power can be supplied to the heave compensation when the crane operator has the feeling that the heave is not compensated sufficiently. For example, the crane operator thus is able to flexible react to changes of the weather and the heave.
Advantageously, the change of the division of the available at least one kinematically constrained quantity is effected as described above by varying the weighting factor.
Advantageously, the crane controller according to the present disclosure includes a calculation function which calculates the currently available at least one kinematically constrained quantity. In particular, the maximum available power and/or velocity and/or acceleration of the hoisting gear can be calculated. Since the maximum available power and the maximum available velocity and/or acceleration of the hoisting gear can change during the lift, the same thus can be adapted to the current circumstances of the lift via the calculation function.
Advantageously, the calculation function takes account of the length of the unwound cable and/or the cable force and/or the power available for driving the hoisting gear. For example, depending on the length of the unwound cable the maximum available velocity and/or acceleration of the hoisting gear can be different, since especially during lifts with very long cables the weight of the unwound cable exerts a load on the hoisting gear. In addition, the maximum available velocity and/or acceleration of the hoisting gear can fluctuate depending on the mass of the lifted load. Furthermore, in particular when a hybrid drive with an accumulator is used, the power available for driving the hoisting gear can fluctuate depending on the accumulator condition. Advantageously, this will also be taken into account.
According to the present disclosure, the currently available at least one kinematically constrained quantity each advantageously is split up between heave compensation and operator control according to the specification of the crane operator, in particular with reference to the weighting factor specified by the crane operator.
Advantageously, the optimization function of the heave compensation initially can include a change in the division of the available at least one kinematically constrained quantity and/or a change of the available at least one kinematically constrained quantity during a lift only at the end of the prediction horizon. This provides for a stable optimization function over the entire prediction horizon. Advantageously, with progressing time the changed available at least one kinematically constrained quantity will then be pushed through to the beginning of the prediction horizon.
Advantageously, the optimization function of the heave compensation according to the present disclosure determines a target trajectory which is included in the control and/or regulation of the hoisting gear. In particular, the target trajectory is meant to specify a target movement of the hoisting gear. The optimization can be effected via a discretization.
According to the present disclosure, the optimization can be effected at each time step on the basis of an updated prediction of the movement of the load lifting point.
According to the present disclosure, the first value of the target trajectory each can be used for controlling the hoisting gear. When an updated target trajectory then is available, only the first value thereof will in turn be used for the control.
According to the present disclosure, the optimization function can operate with a greater scan time than the control. This provides for choosing greater scan times for the calculation-intensive optimization function, for the less calculation-intensive control, on the other hand, a greater accuracy due to lower scan times.
Furthermore, it can be provided that the optimization function makes use of an emergency trajectory planning when no valid solution can be found. In this way, a proper operation also is ensured when a valid solution cannot be found.
Advantageously, the operator control calculates the velocity of the hoisting winch desired by the operator with reference to a signal specified by an operator through an input device. In particular, a hand lever can be provided.
The desired velocity can be calculated for the operator control as the part of the maximum available velocity specified by the position of the input device.
Advantageously, the target trajectory is generated by integration of the maximum admissible positive jerk, until the maximum acceleration is achieved. It thereby is ensured that the hoisting gear is not overloaded by the operator control. Advantageously, the maximum acceleration corresponds to the part of the maximum available acceleration of the hoisting gear which is assigned to the operator control.
Furthermore advantageously, the velocity thereupon is increased by integration of the maximum acceleration, until the desired velocity can be achieved by adding the maximum negative jerk.
It thereby is ensured that on achieving the target velocity, the acceleration again has decreased to zero, so that unnecessary loads by an acceleration jump on reaching the target velocity are avoided.
The present disclosure furthermore comprises a crane with a crane controller as it has been described above.
In particular, the crane can be arranged on a pontoon. In particular, the crane can be a deck crane. Alternatively, it can also be an offshore crane, a harbor crane or a cable excavator.
The present disclosure furthermore comprises a pontoon with a crane according to the present disclosure, in particular a ship with a crane according to the present disclosure.
Furthermore, the present disclosure comprises the use of a crane according to the present disclosure and a crane controller according to the present disclosure for lifting and/or lowering a load located in water and/or the use of a crane according to the present disclosure and a crane controller according to the present disclosure for lifting and/or lowering a load from and/or to a load deposition position located in water, for example on a ship. In particular, the present disclosure comprises the use of the crane according to the present disclosure and the crane controller according to the present disclosure for deep-sea lifts and/or for loading and/or unloading ships.
The present disclosure furthermore comprises a method for controlling a crane which includes a hoisting gear for lifting a load hanging on a cable. Advantageously, a heave compensation at least partly compensates the movement of the cable suspension point and/or load deposition point due to the heave by an automatic actuation of the hoisting gear. Furthermore, the hoisting gear is actuated with reference to specifications of the operator via an operator control. In accordance with the present disclosure it is provided according to a first aspect that at least one kinematically constrained quantity of the hoisting gear is variably split up between the heave compensation and the operator control. According to a second aspect it is provided that trajectories for the heave compensation and for the operator control are calculated separate from each other. The method according to the present disclosure hence provides the same advantages which have already been described above with regard to the crane controller. Again, the two aspects may be combined with each other.
The method is carried out such as has already been set forth in detail in accordance with the present disclosure with regard to the crane controller and its function. Furthermore advantageously, the method according to the present disclosure serves the use which likewise has already been set forth above.
In particular, the method according to the present disclosure can be carried out by means of a crane controller as it has been set forth above and/or by means of a crane as it has been set forth above.
The present disclosure furthermore comprises software with code for carrying out a method according to the present disclosure. In particular, the software can be stored on a machine-readable data carrier. Advantageously, a crane controller according to the present disclosure can be implemented by installing the software according to the present disclosure on a crane controller.
The present disclosure will now be explained in detail with reference to an exemplary embodiment and drawings.